The following abbreviations are utilized herein:    AP access point    CSG closed subscriber group    DTX discontinuous transmission    eNB E-UTRAN node B, evolved node B    E-UTRAN evolved universal terrestrial radio access network    FSU flexible spectrum use    IE information element    IMT-2000 international mobile telephony-2000    IMT-A international mobile telephony-advanced    IP internet protocol    IPSec IP security    L2 layer 2 (medium access control, MAC)    LAN local area network    Node B base station    O&M operation and maintenance    PLMN public land mobile network    RF radio frequency    SS spectrum sharing    TCP transmission control protocol    UDP user datagram protocol    UE user equipment, such as a mobile station or mobile terminal    WLAN wireless local area network
FSU generally refers to any spatially and/or temporally varying use of radio spectrum/radio resources. As a non-limiting example, FSU enables networks of different operators to operate on a same radio spectrum (using the same shared radio resources). FSU allows a plurality of operators to collectively utilize a frequency band such that there are no dedicated portions licensed to a single operator. The frequency band may still be licensed, however regulatory rules will dictate how bandwidth sharing is executed. This allows each operator to adjust its frequency use according to local needs such that the scarce spectrum is more efficiently utilized than in non-FSU models (e.g., the current regulation model). FSU may also be applied on an unlicensed band, though the flexible spectrum use would still have to be regulated so that the networks can reliably operate.
SS generally refers to situations in which different systems and/or sub-systems utilize the same part of a spectrum in a coordinated or uncoordinated manner. A special case of SS is band-sharing based on FSU. Typically, the sharing systems are based on similar technologies and offer similar services. For example, different operators may share the same spectrum by utilizing dynamic channel assignment from a common pool of channels.
IMT-A refers to radio access systems beyond IMT-2000 having a new, global, unified wireless architecture which: (i) visualize a hierarchy of interconnected access systems; (ii) envision new radio interfaces for mobile classes targeting at data rates of 100 Mbps and nomadic/local-area classes targeting at 1 Gbps; and (iii) include operation on new (i.e., yet to be assigned) spectrums or frequency bands to be licensed. Unlicensed operation will also be in the scope of IMT-A.
Reference with regard to background and general concepts of FSU for IMT-A systems may be made to IST-2003-507581 WINNER D6.1: WINNER Spectrum Aspects: Methods for Efficient Sharing, Flexible Spectrum Use and Coexistence, Oct. 30, 2004.